If you have Gimp I tell you what: It is the most time consumption of my life and tedious in every way which is harder than editing animation for Photoshop. In terms of pixel art anti aliasing is easy for my just add a 1px shadow on the outside edge depending what light scource direction it was. If you want to learn more about pixel art here it is: http://www.retronator.com/post/79888759543/no-bullshit-pixel-art-tutorial-week-1